You can now download Frank Herbert's Dune Messiah for only 1.99$ here. There is a price match in Canada.

Here's the blurb:

Book Two in the Magnificent Dune Chronicles—the Bestselling Science Fiction Adventure of All Time.Dune Messiah continues the story of Paul Atreides, better known—and feared—as the man christened Muad’Dib. As Emperor of the Known Universe, he possesses more power than a single man was ever meant to wield. Worshipped as a religious icon by the fanatical Fremens, Paul faces the enmity of the political houses he displaced when he assumed the throne—and a conspiracy conducted within his own sphere of influence.And even as House Atreides begins to crumble around him from the machinations of his enemies, the true threat to Paul comes to his lover, Chani, and the unborn heir to his family’s dynasty...

You can also get your hands on the digital edition of David Walton's The Genius Plague for only 1.99$ here.

Here's the blurb:

THE CONTAGION IS IN YOUR MIND.In this science fiction thriller, brothers are pitted against each other as a pandemic threatens to destabilize world governments by exerting a subtle mind control over survivors.Neil Johns has just started his dream job as a code breaker in the NSA when his brother, Paul, a mycologist, goes missing on a trip to collect samples in the Amazon jungle. Paul returns with a gap in his memory and a fungal infection that almost kills him. But once he recuperates, he has enhanced communication, memory, and pattern recognition. Meanwhile, something is happening in South America; others, like Paul, have also fallen ill and recovered with abilities they didn’t have before.But that’s not the only pattern–the survivors, from entire remote Brazilian tribes to American tourists, all seem to be working toward a common, and deadly, goal. Neil soon uncovers a secret and unexplained alliance between governments that have traditionally been enemies. Meanwhile Paul becomes increasingly secretive and erratic.Paul sees the fungus as the next stage of human evolution, while Neil is convinced that it is driving its human hosts to destruction. Brother must oppose brother on an increasingly fraught international stage, with the stakes: the free will of every human on earth. Can humanity use this force for good, or are we becoming the pawns of an utterly alien intelligence?